This invention relates to machine tool construction in general and, in particular, to a new and useful machine tool having a work carrier which is mounted for movement in a carrier guide which, in turn, is supported for movement at right angles to the work carrier and the machine frame and, wherein, a work holder is also movable along the work carrier and may be fixed to the carrier for movement therewith and wherein each work holder may be locked by a locking device oriented over the carrier and engageable into a locking recess of the work holder when the work holder is precisely positioned in respect to a locking element of the locking device.